Robert Frost wrote in both _________ and the free verse, and sometimes he wrote in a form that borrows freely from the merits of both.
A、blank verse
B、sonnet
C、rhyming couplets
D、the metrical forms
【正确答案】：D
【题目解析】：教材563第二段。在诗体形式上，弗洛斯特既写格律诗又写自由诗，有时是两者的自由结合。